JP2006513925A - Engine compartment partition layer - Google Patents

Abstract

Regarding the formation of the sound insulation and sound absorption cavity (8) in the engine room (1), the engine room (1) is partitioned by a lightweight engine room partition layer (7). The partition layer (7) can be made from several parts and forms a substantially sticky surface in the engine room (1). In a preferred embodiment of the present invention, the partition layer (7) includes a carrier layer (12) and a sound absorbing layer (13), and includes a first waterproof / oilproof layer (14) and a second waterproof / oilproof layer ( 15). The cavity (8) created by this partition layer (7) substantially increases the transmission loss.

Description

  The present invention relates to an engine compartment partition layer used in an automobile engine compartment.

  The goal of the modern automobile industry is to provide a vehicle that not only has a soundproof environment in the passenger compartment, but also does not emit annoying noise. In particular, knocking noise in the low frequency range of 800 to 2000 Hz and other types of specific noise patterns emitted by diesel vehicles are considered undesirable in the automotive industry. Unpleasant noise in the high frequency range of 1000 to 5000 Hz emitted by the engine assembly is also undesirable.

  In order to reduce the noise level emitted to the outside, in particular in the case of heavy goods vehicles or trucks, the motor, individual devices (eg transmission or transmission) or the engine bay or the entire engine room are wrapped in sound insulation. It is known to protect. In general, a sound-proofing lining is provided in the engine compartment of a normal passenger car, and in particular a noise attenuation layer is provided on the bonnet and / or the front wall. These linings were essentially in the form of sound insulation and had only a limited soundproofing effect.

  These measures do not seem to meet the soundproofing requirements preset by the automotive industry. No matter how the sound insulation value of these linings is improved, the thickness and weight of the lining increase.

  Therefore, it is an object of the present invention to further reduce or completely eliminate the noise emitted from the engine compartment in an efficient manner. In particular, it is an object of the present invention to provide a lightweight and soundproofing means for reducing emitted noise.

  This is achieved according to the invention by providing an engine compartment partition layer comprising the features of claim 1. In the following, the term “partition layer” relates to various sheet-like components which are arranged between the bonnet and the base part of the engine room and which partition the engine room preferably horizontally.

  By this partition layer, a soundproof chamber or cavity is formed in the engine room, and the sound field energy generated by the engine or other vehicle device is reduced by the sound absorption and sound insulation effects.

  In a preferred embodiment of the invention, this partition layer is arranged to lie substantially horizontally, i.e. parallel to the vehicle floor, on a few centimeters of the engine block, e.g. 4-5 cm. In this way, a substantially closed and soundproofing cavity is formed between the closed bonnet and this partition layer. By placing the soundproofing cavity in such a place, a soundproofing effect and several different sound absorbing effects can occur. It will be appreciated that depending on the particular sound insulation requirements, the dimensions of this cavity can be adjusted by specifically designing the partition layer of the present invention. In addition, the partition layer may be provided with additional sound absorbing or insulating material to solve the problem more efficiently.

  In particular, the cavity with soundproofing effect created by the engine compartment partition layer according to the present invention substantially functions in a large Helmholtz resonator system including sound absorbing and sound insulating walls. This allows a person skilled in the art to adjust the sound field radiated out of the vehicle in an easy and cost-effective manner.

  In a particular embodiment of the invention, the engine compartment partition layer consists of a plurality of parts that are joined and complementary to each other.

  In another embodiment of the present invention, several engine room partition layers are arranged in the same engine room to form several soundproofing cavities. In particular, the individual partition layers can interact in a Helmholtz resonator manner.

  Other preferred embodiments of the invention or other developments to the invention include the features of the dependent claims. In particular, the partition layer includes a carrier layer and a sound absorbing layer. This carrier layer consists of a compressed phenolic nonwoven layer or a suitable foam material. The carrier layer is preferably provided with a first waterproof / oilproof layer, particularly a woven scrim or felt layer, on the bonnet side. Furthermore, the sound-absorbing layer comprises in particular a slightly compressed phenolic resin layer, in particular a woven scrim or a felt layer. The person skilled in the art understands that any suitable sound-absorbing material can be chosen, in particular an open-cell foam. The sound absorbing layer may be provided with a second waterproof / oil-proof layer, particularly a woven scrim or felt layer, on the engine room floor or the ground side.

  The partition layer may also be made from several parts that are bondable and complementary to each other, as appropriate for the particular assembly requirements within the engine room.

  In the partition layer according to the invention, in order to increase the sound absorption effect for the Helmholtz resonator, at least one soundproofing aperture is further developed. In addition, these pores can also help drain water or oil proof residues or other liquid waste materials from the cavities. Those skilled in the art may also consider forming such a plurality of cavities in the engine room and may change the size of these cavities to adjust the soundproofing characteristics.

  Considering the overall soundproofing characteristics of the vehicle, the transmission loss and the characteristics that affect the sound absorption coefficient, and secondly, considering the improvement of the transmission loss, the engine room partition layer according to the present invention can be used from the engine room. The leakage of acoustic energy is actually reduced. It can be seen that the measurements show that the sound absorption rate of the arrangement according to the invention increases considerably in the frequency range between 100-400 Hz and 1000-5000 Hz. Improvements at high frequencies are related to the airflow resistance of the scrim layer, and improvements in the low frequency range are substantially due to the sound absorption effect of the cavity.

  The invention is explained in more detail by means of exemplary embodiments and using the drawings.

  The schematic section according to FIG. 1 shows an engine room 1 in which an engine 2 and a vehicle unit or assembly 3 are arranged. The engine room 1 is provided with a lining that attenuates sound, in particular, a front wall lining 4 and a bonnet lining 5. A vehicle having an engine floor lining 6 is also known. Such linings are well known to those skilled in the art and are not the object of the present invention.

  The schematic section according to FIG. 2 shows an engine room 1 comprising an engine room partition layer 7 according to the invention. The partition layer 7 is disposed immediately above the engine 2 and is substantially closed to form a cavity 8 having a soundproofing effect in the closed engine room 1. In a preferred embodiment of the present invention, the partition layer 7 is a two-layered structure including a carrier layer 12 on the bonnet side, particularly a compression felt layer containing phenol resin, and a first waterproof / oilproof layer 14, particularly A woven scrim, non-woven or felt layer is provided. On the engine room floor side or on the ground side, the two partition layers 7 are provided with a second waterproof / oil-proof layer 15, in particular, a felt layer (sound absorbing layer) containing phenol resin and slightly compressed. Further, the engine room 1 shown in FIG. 2 has a normal bonnet lining 5 and a normal front wall lining 4. By adding the second partition layer 9, the second cavity 10 is formed. Alternatively, when the floor lining 6 is provided in the engine room 1, the third cavity 11 is formed. These partition layers (6, 7, 9) are designed so that they correspond to the outer shape of the engine 2 or other vehicle apparatus or assembly 3 in the engine room 1. Furthermore, it is possible to design such that openings are formed in these partition layers, and individual devices or assemblies protrude from the openings in close contact with each other. That is, it can be designed in a color shape.

  It will be understood that the partition layers 7 and 9 according to the present invention are formed so as to be easily removed from the engine room 1 for vehicle maintenance. It is preferable that the partition layers 7 and 9 are formed by joining some parts. Suitable joining means are well known to those skilled in the art.

  FIG. 3 shows a more detailed schematic view of the engine room 1 including the engine 2 and having a preferable configuration of the partition layer 7 of the present invention. Here, the partition layer 7 is disposed on the upper part of the engine and forms a cavity 8 having a soundproofing effect together with the closed bonnet 17. The partition layer 7 includes a carrier layer 12 and a sound absorbing layer 13. This two-layer structure preferably includes a first waterproof / oil-proof layer 14 on the bonnet side and a second waterproof / oil-proof layer 15 on the side facing the engine room 1 or the ground. The bonnet 17 is preferably covered with a normal lining material 18 on the engine side. It has been found that it is preferable to have a thin air layer between the first waterproof / oilproof layer 14 and / or the second waterproof / oilproof layer 15 and the partition layer 7. This figure further shows an optional, soundproofing ostium 16, which may also help to discharge liquid waste material. It is within the skill of the artisan to select an appropriate material for the design of the engine compartment partition layer 7 of the present invention.

In FIG. 4, the fluctuation | variation with the frequency of the sound absorption rate of the structure which concerns on this invention is shown with a graph. The specific configuration used for the calculation of the soundproofing properties, in particular the sound absorption coefficient, is as follows.
-A steel plate with a thickness of 0.8 mm (representing a bonnet),
-A space with a depth of 0.001 mm,
-1 mm thick lining material,
-A space 20-50 mm deep (representing a cavity),
A first waterproof and oilproof layer of 1 mm thickness, consisting of 100 g / m ² of PET felt plus 20 g / m ² of thermoplastic resin adhesive (eg SURLYN®),
A 4 mm thick carrier layer consisting of 1200 g / m ² of phenol felt;
A 20 mm thick sound absorbing layer of 500 g / m ² PET felt covering 80% of the entire surface,
A second waterproof and oilproof layer of 1 mm thickness consisting of 80 g / m ² of PET felt plus 20 g / m ² of thermoplastic resin adhesive.

  This configuration corresponds to the configuration shown in FIG. The value of the sound absorption coefficient that varies with frequency related to this configuration is shown by a curve A in FIG.

To demonstrate the implementation of the inventive concept, a comparative calculation was performed on a conventional multilayer bonnet liner including:
-A steel plate with a thickness of 0.8 mm,
-0.001 mm thin air layer,
-A 20 mm thick sound absorbing layer (Thinsulate® covering 80% of the entire surface),
-A compression felt (carrier) with a thickness of 4.7 mm;
The value of the sound absorption coefficient that varies with frequency in relation to this comparative configuration is shown by curve B in FIG.

  Finally, curve C in FIG. 4 shows a typical and common felt value of 20 mm thickness, which reveals the improvement obtained by the present invention.

  The advantage of the engine compartment partition of the present invention is that it reduces the emission of sound outside the vehicle, particularly in the desired frequency range, as occurs when a vehicle with or without cargo travels around the city. But it will be obvious immediately. This reduction in sound emission results in increased transmission losses due to the partition layer of the present invention. It is understood that by using several partition layers, the emission of these sounds can be further reduced. In particular, the soundproofing effect of the individual cavities formed according to the present invention by the appropriate design and by providing the soundproofing lining part and the appropriate small holes with soundproofing effect in the individual partition layers. Can be optimized.

  It can be seen that a further effect can be obtained by reducing the weight compared to the conventional liner concept. In particular, such a lightweight partition layer can be used instead of the usual heavy layer damping material.

  According to the first measurement in such a configuration, it was shown that the use of the partition layer 7 leads to a reduction of the radiated sound level (increase of transmission loss) of about 4 dB in the range of 800 to 2000 Hz. .

During these measurements, the sound absorption in this frequency range was between 0.2 and 0.85. Two partition layers 7 are used for these measurements, the carrier layer 12 has a density of 450 kg / m ³ , the air flow resistance is 2400 Rayls, and the sound absorbing layer 13 has a density of It was 80 kg / m ³ and the airflow resistance was 600 Rayls.

  Further developments of the partition layer according to the present invention may include thermal protection, sound absorption or conductive members.

It is a schematic cross section of an engine room provided with a normal sound absorption lining according to the technical level. It is a schematic cross section of the engine room which has a partition layer concerning the present invention. FIG. 3 is a schematic cross section showing an engine room provided with a partition layer according to the present invention in more detail than that shown in FIG. 2. It is a figure which shows the fluctuation | variation by the frequency of the sound absorption coefficient of the structure which concerns on this invention.

Claims (11)

  The engine room used in the engine room (1) which partitions the engine room (1) and forms at least one cavity (8) having a soundproofing effect in the closed engine room (1). Partition layer.   The partition layer according to claim 1, wherein the partition layer (7) includes a carrier layer (12) and a sound absorbing layer (13).   The partition layer of claim 2, wherein the carrier layer (12) comprises a compressed phenolic resin nonwoven layer.   The partition layer according to claim 3, wherein the carrier layer (12) is provided with a first waterproof / oilproof layer (14), in particular a woven scrim or felt layer, on the bonnet side.   The partition layer according to claim 2, wherein the sound absorbing layer (13) comprises a slightly compressed phenolic resin layer, in particular a woven scrim or a felt layer.   The partition layer according to claim 5, wherein the sound absorbing layer (13) is provided with a second waterproof / oilproof layer (15), in particular a woven scrim or felt layer, on the engine room floor or ground side.   The partition layer according to any one of claims 1 to 6, wherein the partition layer (7) is composed of several parts that can be joined and are complementary to each other.   The partition layer according to any one of claims 1 to 7, wherein the partition layer (7) is provided with at least one small hole (16) having a soundproofing effect.   Use of the engine compartment partition layer (7) according to claim 1 in the engine compartment (1).   In order to form a plurality of soundproofing cavities (8, 10) in the engine room (1), several engine room partition layers (7, 9) according to claim 1 are connected to the engine room (1). ) Method used within. Use of several engine compartment partition layers (7, 9) according to claim 9, wherein the cavities (8, 10) have different volumes.

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